The activities of the enzymes of the pathway of uric acid synthesis responsible for the adaptation of chick liver to a high protein diet have been measured. Major factors which determine the stability of glutathione in hepatocytes in the presence of cysteine and ammonium chloride have been identified as unsaturated fatty acids, especially polyunsaturates. The antifungal effects of benzoic acid in preserving acidic foods, such as fruit juices, has been found to be due to the acidification of yeast cells brought about by the entry into the cell of undissociated benzoic acid. The study of the metabolism of branched-chain fatty acids and of the corresponding 2-oxoacids (with the help of purified branched-chain amino dehydrogenase from B. subtilis) has supplied information on the role of liver and muscle in branched-chain amino metabolism and revealed differences between man and rat. Work on the role of prolactin in the control of lipogenesis in the lactating rat has led to the working hypothesis that the elevation of prolactin in response to the suckling stimulus results in a depression of lipogenesis in liver and adipose tissue so that glucose and lactate, the two main lipogenic precursors, are made available for the lactating mammary gland.